Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Synchrotron radiation induced fluorescence spectroscopy of gas phase molecules
KTH, Superseded Departments, Physics.
2004 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

A new experimental set-up for gas phase fluorescence studies using synchrotron radiation has been designed and constructed to perform simultaneously total and dispersed fluorescence measurements.

Neutral photodissociation of CO has been investigated after excitation with 19-26 eV photons. Fluorescence from 3p 3P, 3p 3S and 3p 1D excited states in carbon was recorded and interpreted by ab initio calculations. The population and dissociation of states belonging to the C and D Rydberg series in CO seem to explain the production of the observed triplet states but not the 3p 1D state.

Neutral photodissociation of NO is reported in the 17-26 eV energy range. No known molecular states can account for the collected data. New information regarding the precursor states of the observed neutral dissociation is provided by ab initio calculations.

Autoionization of superexcited states in molecular nitrogen is evidenced by strong deviations of the Franck-Condon ratio in the fluorescence of the N2+ B state. Ab initio calculations predict the existence of autoionizing-excited states that may account for some of the observed structures in the 20-46 eV energy range.

Selective molecular fluorescence from the npó1Óu+ and npð 1Ðu (n=3-7) Rydberg levels to the E,F 1Óg+ state in H2 was recorded and rotationally analyzed. Vibrational levels of the E,F 1Óg+ state (vEF =0,1,3,6-10) are determined. The predissociation of npð 1Ð+ levels is observed in agreement with the literature.

Fragmentation of SF6 was investigated after excitation with 25–80 eV photons. Dispersed fluorescence measurements reveal the emission of S, S+, F and F+ excited atoms. These fragments are produced after single, double and triple excitations as well as direct ionizations and shake-ups in SF6.

Photoabsorption and fluorescence yield have been measured in SF5CF3 using 10-30eV photons. The photoabsorption spectrum can be explained in terms of its similarities to those of the SF6 and CF4 molecules. The dispersed and un-dispersed fluorescence resemble those of the CF3X family. Several features suggest the migration of an F atom across the S-C bond that fragments the molecule producing excited CF4.

Doubly excited states of H2 have been investigated in the range of 26-60 eV by monitoring Balmer á emission. The experimental data show the already known emission correlated with the fragmentation of the Q1 and Q2 states, and new features which could be attributed to dissociative photoionization and higher lying doubly excited states Qn (n>2) of the hydrogen molecule

Place, publisher, year, edition, pages
Stockholm: Fysik , 2004.
Series
Trita-FYS, ISSN 0280-316X ; 2004:63
Keyword [en]
Physics, molecular spectroscopy, photon induced fluorescence, synchrotron radiation, superexcited states
Keyword [sv]
Fysik
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-43ISBN: 91-7283-877-9 (print)OAI: oai:DiVA.org:kth-43DiVA: diva2:11703
Public defence
2004-11-12, FB53, AlbaNova, Stockholm, 10:00
Opponent
Supervisors
Available from: 2004-11-30 Created: 2004-11-30 Last updated: 2012-03-20
List of papers
1. Experimental station for gas phase fluorescence spectroscopy
Open this publication in new window or tab >>Experimental station for gas phase fluorescence spectroscopy
Show others...
2004 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 75, no 7, 2402-2408 p.Article in journal (Refereed) Published
Abstract [en]

The details of an experimental setup for gas phase atomic and molecular fluorescence measurements using synchrotron radiation are described in this article. The most significant part of the apparatus is an optical arrangement, which allows for simultaneous measurements of dispersed as well as total fluorescence intensity using an effusive gas jet and an inbuilt gas cell assembled in a convenient plug and measure configuration. The first measurements concerning fluorescence of the N-2 molecule around the N 1s edge obtained with this setup are presented.

Keyword
dispersed fluorescence, n2 molecule, photoionization, n-2, excitation, resonances, states
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-6869 (URN)10.1063/1.1764605 (DOI)000222847900027 ()2-s2.0-3843064413 (Scopus ID)
Note
QC 20100910Available from: 2004-11-30 Created: 2004-11-30 Last updated: 2010-09-10Bibliographically approved
2. Neutral dissociation of superexcited states in carbon monoxide
Open this publication in new window or tab >>Neutral dissociation of superexcited states in carbon monoxide
Show others...
2002 (English)In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 35, no 13, 2975-2983 p.Article in journal (Refereed) Published
Abstract [en]

Neutral photodissociation of CO has been investigated using synchrotron light in the range 19-26 eV by observing dispersed fluorescence from excited neutral C atoms. Follow-up ab initio calculations support the observed neutral carbon excitation functions, which to a large extent are associated with the CO Rydberg - series converging to the CO+ C and D states.

National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-6870 (URN)10.1088/0953-4075/35/13/310 (DOI)000177360600015 ()
Available from: 2004-11-30 Created: 2004-11-30 Last updated: 2011-09-21Bibliographically approved
3. Neutral dissociation of superexcited states in nitric oxide
Open this publication in new window or tab >>Neutral dissociation of superexcited states in nitric oxide
Show others...
2003 (English)In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 293, no 1, 65-73 p.Article in journal (Refereed) Published
Abstract [en]

Near-infrared dispersed fluorescence measurements of 13 different atomic multiplets of neutral atomic fragments from photon induced neutral dissociation processes in NO are reported. For excitation of the molecules narrow band synchrotron photons of energy 17.2-25.8 eV were used. Neither Rydberg series nor other molecular states in NO known so far can account for the collected data. From ab initio calculations we try to obtain more information regarding the NO precursor states, and the mechanism behind the observed neutral dissociation.

National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-6871 (URN)10.1016/S0301-0104(03)00296-9 (DOI)000184681900007 ()
Available from: 2004-11-30 Created: 2004-11-30 Last updated: 2011-09-20Bibliographically approved

Open Access in DiVA

fulltext(1657 kB)1439 downloads
File information
File name FULLTEXT01.pdfFile size 1657 kBChecksum MD5
1cd1a75f8bcaef8a79abb1195a758856d40dc8c6e35a2284a4363092f49e4e8a6e412a82
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Álvarez Ruiz, Jesús
By organisation
Physics
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 1439 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 563 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf